JP2014070914A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably join junction arms to each other in a bobbin regardless of dimensional accuracy of a hollow part of the bobbin.SOLUTION: This invention relates to a split-core current sensor 1 having a magnetic body core 3 split into a plurality of parts. The current sensor 1 includes a bobbin 4 with a coil 5 wound around the outer peripheral surface thereof, split cores 3A and 3B having junction arms 8A and 8B respectively, and a pressing member (leaf spring member 15). The pressing member presses a junction surface 12 of one junction arm 8A inserted from one opening into the bobbin 4, to a junction surface 12 of the other junction arm 8B inserted from the other opening into the bobbin 4.

Description

  The present invention relates to a magnetic balance type current sensor for detecting a current flowing through a conductor in a non-contact manner.

A magnetic balance type current sensor is known as a current sensor for detecting a direct current in a non-contact manner. This current sensor is recognized as a current sensor for detecting a large current, suitable for HEV (hybrid vehicle), EV (electric vehicle), and the like.
The principle of the magnetic balance type current sensor is that a magnetic flux (cancellation magnetic flux) that cancels the magnetic flux generated in the magnetic core by the detected current is generated by the cancellation current of the coil wound around the magnetic core, and this cancellation current is measured. It is taken out as a value.

For this reason, in the magnetic balance type current sensor, a coil (secondary winding) that generates a canceling magnetic flux is mounted in a state of being wound around a part of the magnetic core.
However, since the magnetic core is a substantially annular member in which only the gap is opened, when the coil is directly attached to the magnetic core, the winding must be wound while passing the gap for each turn. The winding work takes a lot of man-hours.

In view of this, a core split type current sensor has been proposed in which a split core is inserted into a bobbin around which a coil is wound in advance, and the split cores are connected to each other inside the bobbin to constitute a magnetic core with a coil. (See Patent Document 1).
8A is a perspective view showing a joining state of the conventional split cores 53A and 53B described in Patent Document 1, and FIG. 8B is a view before the split cores 53A and 53B and the bobbin 54 are assembled. It is a perspective view.

The directions X, Y, and Z shown in FIG. 8 indicate the directions of three-dimensional coordinates for specifying the positions of the constituent members of the magnetic core 53. The X direction may be referred to as “the longitudinal direction of the joining arms 58A and 58B”, the Y direction may be referred to as “the thickness direction of the joining arms 58A and 58B”, and the direction Z may be referred to as “the width direction of the joining arms 58A and 58B”.
As shown in FIG. 8, in the conventional core split type current sensor, the magnetic core 53 is divided into two parts, a first split core 53A and a second split core 53B. These split cores 53A and 53B have joint arms 58A and 58B that are long in the X direction.

Further, the dimension in the width direction Z of each joining arm 58A, 58B is approximately half that of the other part of the magnetic core 53, and the joining surface 62 of each divided core 53A, 53B is in the longitudinal direction X. And the normal direction n is a plane which faces the width direction Z of the joining arms 58A and 58B.
When the joining surfaces 62 are joined to each other and the joining arms 58A and 58B of the divided cores 53A and 53B are overlapped in the width direction Z, a gap 52 is formed in the lower right corner as shown in FIG. A magnetic core 53 having the structure is configured.

8B, the joining arm 58A of the first split core 53A is inserted into the bobbin 54 from the left opening, and the joining arm 58B of the second split core 53B is inserted into the bobbin 4 from the right opening. Then, the joining arms 58A and 58B of the divided cores 53A and 53B are superposed inside the bobbin 4.
In this case, if the bonding arms 58A and 58B in the bobbin 54 are not sufficiently bonded to each other, the magnetic resistance at the bonding surface 62 increases, the magnetic permeability of the magnetic core 53 decreases, and the detection sensitivity of the current sensor decreases. To do.

  Therefore, in the conventional current sensor, the joining arms 58A and 58B in the bobbin 54 are fixed to each other by, for example, tightening force of the hollow part 63 of the bobbin 54 (restoring force generated by elastic deformation or elastic-plastic deformation of the hollow part 63 itself). ).

Japanese Patent Publication No. 7-4588

However, in the means for fixing the joining arms 58A and 58B to each other by the tightening force of the hollow part 63 of the bobbin 54, the entire hollow part 63 of the bobbin 54 is uniform in the longitudinal direction X of the joining surface 62 unless it is molded with high dimensional accuracy. The tightening force cannot be secured.
In other words, when the dimensional error of the hollow portion 63 of the bobbin 54 is large, the adhesion at the joint surface 62 of the portion where the tightening force is weak becomes weak, the magnetic path is divided, and the magnetic permeability of the magnetic core 53 decreases. This may reduce the detection sensitivity of the current sensor.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a core-divided type current sensor capable of reliably joining the joining arms in the bobbin regardless of the dimensional accuracy of the hollow portion of the bobbin. .

  (1) The current sensor according to the present invention is a core split type current sensor in which a magnetic core is divided into a plurality of parts, and includes a bobbin in which a coil is wound around an outer peripheral surface and a joint surface extending in the axial direction of the bobbin. Are joined to each other, and the joining surfaces are joined to each other, and the joining arms are overlapped, so that a plurality of split cores constituting the magnetic core and one of the openings are inserted into the bobbin And a pressing member that press-contacts the joint surface of the one of the joint arms to the joint surface of the other joint arm inserted into the bobbin from the other opening.

According to the current sensor of the present invention, the pressing member presses the joint surface of one joint arm inserted into the bobbin from one opening to the joint surface of the other joint arm inserted into the bobbin from the other opening. Therefore, regardless of the dimensional accuracy of the hollow portion of the bobbin, the joining arms in the bobbin can be reliably joined.
For this reason, it is possible to prevent a decrease in detection sensitivity of the current sensor due to the magnetic path being divided at the joint surface and the magnetic permeability of the magnetic core being lowered.

(2) In the current sensor according to the aspect of the invention, the joint surface is a flat surface whose normal direction is directed to the thickness direction of the joint arm, and the split core is formed so that each part including the joint arm has the same width dimension. It is preferable that
In this case, since the split core can be manufactured only by press molding, compared to the case where a split core having a shape that requires cutting after press molding (for example, the conventional split cores 53A and 53B shown in FIG. 8) is employed. Thus, the manufacturing cost of the current sensor can be reduced.

(3) The current sensor of the present invention further includes a positioning member that positions the relative position of the joint arm in the axial direction with respect to the bobbin by uneven engagement between the bobbin and the joint arm. Is preferred.
In this case, since the positioning member positions the relative position of the joining arm in the axial direction with respect to the bobbin by the concave-convex engagement, the work of assembling the magnetic core to a predetermined dimension is simplified. In addition, if a plurality of concave / convex engagement positions are provided, the gap width can be adjusted.

(4) In the current sensor of the present invention, if the corners that do not affect the magnetic path in the split core are removed, the size and weight of the split core can be reduced, and the performance of the current sensor is effectively secured. However, it is possible to reduce the size.
(5) In the current sensor according to the present invention, if the joint arm is housed in the bobbin with a gap with respect to the inner surface of the bobbin, the magnetic core and the magnetic core Insulation with the coil can be further enhanced.

(6) In the current sensor according to the aspect of the invention, the pressing member may be disposed at a position where the pressing member is in contact with only one of the joining arms to apply a pressing force.
In this case, as compared with the case of a later-described pressing member that abuts on both the joining arms and applies a pressing force, the press contact force on the joining surface is reduced, but there is an advantage that the inner dimension of the bobbin can be made smaller.

(7) Moreover, the said pressing member can also be arrange | positioned in the position which contact | abuts to both the said joining arms and provides pressing force.
In this case, as compared with the case of a pressing member that abuts against one of the joining arms and applies a pressing contact force, the inner dimension of the bobbin is enlarged, but there is an advantage that the pressing force on the joining surface can be further improved.

  As will be described later, specific examples of the pressing member include, for example, a “plate spring member” provided integrally with the bobbin, a “clip member” provided separately on the bobbin, and a bobbin. There are “wedge members” that are driven between the joining arms.

(8) In the current sensor of the present invention, it is preferable that the current sensor further includes a second pressing member for preventing lateral displacement between the joining arms.
In this case, since the second pressing member prevents lateral displacement in the width direction between the joining arms, a decrease in the magnetic permeability of the magnetic core due to the joining surface not being partially joined by the lateral displacement is prevented in advance. can do.

(9) In the current sensor of the present invention, for example, an electromagnetic steel plate, a permalloy plate, and a molded body of magnetic powder can be adopted as the constituent material of the split core.
However, in the case of electromagnetic steel plates and permalloy plates, the permeability in the plate thickness direction is worse than in the in-plane direction, whereas in the case of a magnetic powder molded body, the permeability is almost the same in all directions. There are characteristics. For this reason, in the case of the present invention in which the magnetic path is a path straddling the joint surface, it is preferable to employ a magnetic powder compact.

(10) In the current sensor of the present invention, it is preferable that a gap between the joining arm and the inner surface of the bobbin is hardened with a resin.
In this way, the joining arm and the bobbin can be securely fixed, and the insulation between the magnetic core and the coil can be improved.

  As described above, according to the present invention, the joining arms in the bobbin can be reliably joined regardless of the dimensional accuracy of the hollow portion of the bobbin.

(A) is a front view of the current sensor according to the first embodiment, and (b) is a plan view of the current sensor. (A) is a perspective view which shows the joining state of the split core which concerns on 1st Embodiment, (b) is a perspective view before the assembly of the split core and a bobbin. (A) is a front view of the current sensor which concerns on 2nd Embodiment, (b) is a top view of the current sensor. (A) is a front view of the current sensor which concerns on 3rd Embodiment, (b) is a top view of the current sensor. (A) is a front view of the current sensor which concerns on 4th Embodiment, (b) is a top view of the current sensor. (A) is a front view of the current sensor which concerns on 5th Embodiment, (b) is a top view of the current sensor. It is a rear view of the current sensor which concerns on 5th Embodiment. (A) is a perspective view which shows the joining state of the conventional division | segmentation core, (b) is a perspective view before the assembly of the division | segmentation core and a bobbin.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1A is a front view of the current sensor 1 according to the first embodiment, and FIG. 1B is a plan view of the current sensor 1. In FIG. 1A, the bobbin 4 is shown in a sectional view.
FIG. 2A is a perspective view showing a joined state of the split cores 3A and 3B according to the first embodiment, and FIG. 2B is a perspective view before the split cores 3A and 3B and the bobbin 4 are assembled. It is.

The directions X, Y, and Z shown in FIG. 2 indicate the directions of the three-dimensional coordinates for specifying the positions of the constituent members of the magnetic core 3.
In the following description, the direction X is referred to as “the longitudinal direction of the joining arms 8A and 8B”, the direction Y is referred to as “the thickness direction of the joining arms 8A and 8B”, and the direction Z is referred to as “the width direction of the joining arms 8A and 8B”. is there. The direction X coincides with the axial direction of the bobbin 4 when the joining arms 8A and 8B are inserted through the bobbin 4 (the state shown in FIG. 1).

The current sensor 1 of the present embodiment is a magnetic balance type current sensor, and includes a magnetic core 3 having a substantially C-shape in front view having a gap 2 set on a magnetic path at a predetermined interval, and a magnetic core 3. An insulating bobbin 4 mounted on the upper side of the figure, a coil 5 wound around the outer peripheral surface of the bobbin 4, and a magnetic sensor 6 for detecting magnetic flux as an electric signal are provided.
The magnetic core 3 is divided into two parts, a first divided core 3A and a second divided core 3B, and these divided cores 3A and 3B are formed in a substantially U-shape when viewed from the front.

The first divided core 3A includes a joining arm 8A that is long in the direction X, a vertical side portion 9A that extends downward from the left end of the joining arm 8A in the direction Y, and a lower side portion that extends rightward in the direction X from the lower end of the vertical side portion 9A. 10A, and the lower side portion 10A is approximately half the length of the joining arm 8A.
The second split core 3B includes a joint arm 8B that is long in the direction X, a vertical side portion 9B that extends downward from the right end of the joint arm 8B in the direction Y, and a lower side portion that extends leftward in the direction X from the lower end of the vertical side portion 9B. 10B, and the lower side portion 10B is approximately half the length of the joining arm 8B.

Note that a substantially rectangular protruding portion 11 is formed at the upper end portion of the vertical side portion 9B of the second divided core 3B so that the front end surface of the joining arm 8A of the first divided core 3A abuts.
In each divided core 3A, 3B, the dimension in the thickness direction Y of the joining arms 8A, 8B is smaller than the thickness dimension of the other part of the divided cores 3A, 3B. Further, the joining surface 12 of the joining arms 8A and 8B is a plane extending in the longitudinal direction X of the joining arms 8A and 8B and having the normal direction n facing the thickness direction Y of the joining arms 8A and 8B.

Therefore, when the joining surfaces 12 are joined to each other and the joining arms 8A and 8B of the divided cores 3A and 3B are superposed in the thickness direction Y, as shown in FIG. 2A, the end faces of the lower side portions 10A and 10B A substantially C-shaped magnetic core 3 having a gap 2 therebetween is formed.
2B, the joining arm 8A of the first split core 3A is inserted into the bobbin 4 from the left opening, and the joining arm 8B of the second split core 3B is inserted into the bobbin 4 from the right opening. Then, the joining arms 8A and 8B of the divided cores 3A and 3B are in a state of being overlapped in the thickness direction Y inside the bobbin 4.

The material of the split cores 3A and 3B may be a plate material such as an electromagnetic steel plate or a permalloy plate, but in this embodiment, a “compact compact” that is a compact of magnetic powder is used.
The green compact is typically formed by molding a soft magnetic powder having an insulating coating made of a silicone resin or the like on the surface, or a mixed powder in which a binder is appropriately mixed in addition to the soft magnetic powder, and then forming the insulating coating. It can be obtained by firing at a temperature lower than the heat resistant temperature.

In the production of green compacts, by adjusting the material of soft magnetic powder, the mixing ratio of soft magnetic powder and binder, the amount of various coatings including insulating coatings, etc., and adjusting the molding pressure The saturation magnetic flux density can be changed.
For example, by using soft magnetic powder with a high saturation magnetic flux density, increasing the proportion of soft magnetic material by reducing the amount of binder, or increasing the molding pressure, compacting with high saturation magnetic flux density The body is obtained.

The coil 5 is configured, for example, by aligning and winding a rectangular conducting wire covered with an insulating material such as polyimide resin around a bobbin 4 made of an insulating material.
The coil 5 of this embodiment is a search coil, and is wound around the outer periphery of the bobbin 4 in a direction that cancels out the magnetic field generated by the current to be measured that passes through the magnetic core 3.

The magnetic sensor 6 includes, for example, a Hall element, a magnetic impedance element, a flux gate, or the like.
Although not shown, the output of the magnetic sensor 6 is amplified by an amplifier circuit (not shown), and the amplified signal output from the amplifier circuit is fed back to one end of the coil 5. As a result, a cancel current obtained by amplifying the output from the magnetic sensor 6 is supplied to the coil 5.

That is, in the current sensor 1 of the present embodiment, when a current to be measured flows through a conductive member inserted through the magnetic core 3, an output voltage is generated in the magnetic sensor 6 by a magnetic field corresponding to the current, and the voltage signal is amplified. It is converted into current by the circuit and fed back to the coil 5.
At this time, the canceling current flowing through the coil 5 is converted into voltage so that the canceling magnetic field generated in the coil 5 and the magnetic field generated by the current under measurement cancel each other, and the magnetic field in the gap 2 is always zero. Is measured.

The bobbin 4 is made of an insulating member such as a hard plastic or a metal material coated with a resin. The bobbin 4 includes a rectangular hollow portion 13 and flange portions 14 respectively provided at both ends of the hollow portion 13. Have one.
The flange portion 14 prevents the coil 5 wound around the outer periphery of the hollow portion 13 from being unwound outward in the axial direction.

One of the wall portions constituting the hollow portion 13 of the bobbin 4 is provided with a “pressing member”. The pressing member of the present embodiment includes a leaf spring member 15 formed by cutting and raising the wall portion of the hollow portion 13 inside.
The leaf spring member 15 is bent in the middle in the length direction so that the tip end is warped. For this reason, the bent portion of the leaf spring member 15 abuts on the back surface (surface opposite to the joining surface 12) of the joining arm 8A inserted through the hollow portion 13, and the tip portion thereof does not contact.

As shown in FIG. 1, the leaf spring member 15 abuts against the back surface of one of the two joining arms 8A and 8B inserted through the hollow portion 13 (the upper joining arm 8A in the illustrated example) and elastically deforms, One joining arm 8A is always pressed toward the other joining arm 8B.
For this reason, the leaf spring member 15 presses the joining surface 12 of one joining arm 8A inserted into the bobbin 4 against the joining surface 12 of the other joining arm 8B inserted into the bobbin 4 from the other opening. It functions as a member.

[Effects of First Embodiment]
According to the current sensor 1 of the first embodiment, since the leaf spring member 15 functions as the pressing member, the joining arms 8A and 8B in the bobbin 4 are independent of the dimensional accuracy of the hollow portion 13 of the bobbin 4. Bonding of each other can be performed reliably.
For this reason, it is possible to prevent the detection sensitivity of the current sensor 1 from being lowered due to the magnetic path being divided at the joint surface 12 and the magnetic permeability of the magnetic core 3 being lowered.

In the current sensor 1 of the first embodiment, the joining surface 12 is a plane whose normal direction n is directed to the thickness direction Y of the joining arms 8A and 8B, and both the split cores 3A and 3B are joined to the joining arm 8A. , 8B are formed in the same width dimension.
In this case, the split cores 3A and 3B can be manufactured only by press molding, and compared with the case where a split core having a shape that requires cutting after press molding (for example, the conventional split cores 53A and 53B shown in FIG. 8) is employed. The manufacturing cost of the current sensor 1 can be reduced.

That is, in the conventional split cores 53A and 53B shown in FIG. 8, since the joining arms 58A and 58B are divided into two in the width direction Z, a step surface is formed at the base of the joining arms 58A and 58B. 53B becomes a complicated shape that cannot be produced without a cutting process.
In this regard, in the split cores 3A and 3B of the first embodiment, no stepped surface is formed at the roots of the joining arms 8A and 8B, and the front shape is constant no matter where in the width direction Z is cut. 3B can be manufactured only by press molding.

Further, in the current sensor 1 of the first embodiment, since the joining arm 8A is pressed by the leaf spring member 15 formed in the hollow portion 13, the gap is formed between the inner surface of the hollow portion 13 of the bobbin 4 and the joining arm 8A. A gap is formed.
For this reason, compared with the conventional current sensor 1 shown in FIG. 8 in which such a gap is not formed, there is an advantage that the insulation between the magnetic core 3 and the coil 5 is further enhanced.

In the current sensor 1 according to the first embodiment, the constituent material of the split cores 3A and 3B is formed of a magnetic powder molded body. Therefore, the magnetic core 3 is made of a magnetic steel plate or a permalloy plate. Magnetic permeability can be improved.
That is, when the split cores 3A and 3B are configured with electromagnetic steel plates or permalloy plates, the thickness direction is normally manufactured so as to coincide with the thickness direction Y of the joining arms 8A and 8B. Perm alloy plates have poor permeability in the thickness direction.

On the other hand, in the core-divided magnetic core 3, the magnetic path always crosses the bonding surface 12, and becomes a path having a component in the thickness direction Y of the bonding arms 8A and 8B. Therefore, in the case of an electromagnetic steel plate or a permanent alloy plate having a poor permeability in the thickness direction, the permeability at the portion where the joining arms 8A and 8B overlap is worse than the other portions, and the desired detection sensitivity may not be obtained. is there.
On the other hand, the magnetic powder molded body has substantially the same permeability in all directions, and the permeability of the portion where the joining arms 8A and 8B overlap does not deteriorate so much. It can be said that it is more excellent as a material.

[Second Embodiment]
FIG. 3A is a front view of the current sensor 1 according to the second embodiment, and FIG. 3B is a plan view of the current sensor 1. In FIG. 3A, the bobbin 4 is shown in a sectional view.
The current sensor 1 according to the second embodiment is different from the current sensor 1 according to the first embodiment (FIG. 1) in that a pair of pressing members made of leaf spring members 15 are provided in the hollow portion 13 of the bobbin 4 in a vertical direction. In the point.

That is, as shown in FIG. 3A, the upper leaf spring member 15 is disposed near the left opening of the hollow portion 13 and presses the back surface of the upper joining arm 8A from above.
Further, the lower leaf spring member 15 is disposed in the vicinity of the right opening of the hollow portion 13 and presses the back surface of the lower joining arm from below.

[Effects of Second Embodiment]
According to the current sensor 1 of the second embodiment, the pressing member composed of the leaf spring member 15 is disposed at a position where the pressing member abuts against both the joining arms 8A and 8B that are overlapped by the hollow portion 13 to apply the pressing force. Therefore, as compared with the current sensor 1 of the first embodiment, the pressing force accompanying the elastic deformation is doubled, and the pressing force on the bonding surface 12 can be improved.

However, if the pressing members made of the leaf spring members 15 are arranged on both the upper and lower sides, the inner dimensions of the bobbin 4 in the thickness direction Y of the joining arms 8A and 8B of the bobbin 4 are enlarged. From the viewpoint of making the current sensor 1 compact, the current sensor 1 of the first embodiment is preferable.
Note that the current sensor 1 of the second embodiment is the same as that of the first embodiment (FIG. 1) except for the above-described configuration, and thus has the same effects as those of the first embodiment.

[Third Embodiment]
FIG. 4A is a front view of the current sensor 1 according to the third embodiment, and FIG. 4B is a plan view of the current sensor 1. In FIG. 4A, the bobbin 4 is shown in a sectional view.
The current sensor 1 according to the third embodiment is different from the current sensor 1 according to the second embodiment (FIG. 3) in that the relative position in the axial direction X of the joint arms 8A and 8B with respect to the bobbin 4 is determined by uneven engagement. The positioning member 17 is provided.

In the third embodiment, the positioning member 17 includes a protrusion 18 on the bobbin 4 side and a concave groove 19 on the joining arms 8A and 8B.
That is, as shown in FIG. 4 (a), a protrusion 18 having a sharp tip is formed on the inner edge of both openings of the bobbin 4, and the protrusion is formed on the back of each joint arm 8A, 8B. A concave groove portion 19 is formed to engage the tip of 18. A plurality of the recessed groove portions 19 are formed side by side in the longitudinal direction X of the joining arms 8A and 8B.

In this case, when the protrusion 18 is fitted into any of the concave grooves 19, the movement of the joining arms 8A and 8B in the axial direction X with respect to the bobbin 4 is restricted.
Therefore, the protruding portion 18 and the recessed groove portion 19 of the third embodiment constitute a positioning member 17 that positions the relative position in the axial direction X of the joining arms 8A and 8B with respect to the bobbin 4 by their concave-convex engagement. ing.

[Effect of the third embodiment]
According to the current sensor 1 of the third embodiment, the relative position in the axial direction X of the joining arms 8A and 8B with respect to the bobbin 4 can be positioned by the concave and convex engagement by the positioning member 17, and therefore the bobbins of the joining arms 8A and 8B The insertion depth with respect to 4 can be easily determined, and the work of assembling the magnetic core 3 to a predetermined dimension is simplified. In addition, since this effect is effective even when the number of the concave groove portions 19 is one, it is not always necessary to provide a plurality of the concave groove portions 19.

Further, in the current sensor 1 of the third embodiment, since the plurality of concave groove portions 19 are provided in the axial direction X, the advantage that the width of the gap 2 can be adjusted by selecting any one of the concave groove portions 19 is provided. There is also.
Since the current sensor 1 of the third embodiment is the same as that of the second embodiment (FIG. 3) except for the configuration described above, the same effects as those of the second embodiment are achieved.

[Fourth Embodiment]
FIG. 5A is a front view of the current sensor 1 according to the fourth embodiment, and FIG. 5B is a plan view of the current sensor 1. In FIG. 5A, the bobbin 4 is shown in a sectional view.
The current sensor 1 of the fourth embodiment is different from the current sensor 1 of the second embodiment (FIG. 3) in that the pressing members provided in a pair of upper and lower portions in the hollow portion 13 of the bobbin 4 are not leaf spring members 15 but bobbins. 4 and the clip member 20 which is a separate body.

That is, as shown in FIG. 5 (a), the upper clip member 20 is attached with its base end fitted into a recess formed in the left opening edge of the bobbin 4, and the upper joining arm 8A. The back surface of this is pressed from above.
Further, the lower clip member 20 is attached by fitting its base end portion to a recess formed in the right opening edge of the bobbin 4, and presses the back surface of the lower joining arm 8B from below. Yes.

[Effects of Fourth Embodiment]
According to the current sensor 1 of the fourth embodiment, the pressing member is not the leaf spring member 15 formed integrally with the bobbin 4 but the bobbin 4 has a configuration in which the clip member 20 of another member is retrofitted to the bobbin 4. The structure of the hollow portion 13 of the bobbin 4 is simple as in the prior art. Therefore, there is an advantage that the bobbin 4 can be easily manufactured.
Note that the current sensor 1 of the fourth embodiment is the same as the second embodiment (FIG. 3) in the configuration other than the above, and therefore has the same effects as those of the second embodiment.

In the example of FIG. 5, the case where the clip member 20 is arranged on both the upper and lower sides is illustrated, but only one clip member 20 is provided in the same manner as the leaf spring member 15 of the first embodiment (FIG. 1). You may decide.
Further, the pressing member is not limited to the leaf spring member 15 integrated with the bobbin 4 or the clip member 20 previously connected to the bobbin 4, but between the inner surface of the hollow portion 13 and the joining arms 8A and 8B. It may be a “wedge member” (not shown) that is used by being driven into the gap.

[Fifth Embodiment]
FIG. 6A is a front view of the current sensor 1 according to the fifth embodiment, and FIG. 6B is a plan view of the current sensor 1. FIG. 7 is a rear view of the current sensor 1 according to the fifth embodiment. In FIG. 6A, the bobbin 4 is shown in a sectional view.
The current sensor 1 of the fifth embodiment is different from the current sensor 1 of the first embodiment (FIG. 1) as a second pressing member for preventing lateral displacement in the width direction Z between the joining arms 8A and 8B. The clip member 20 is further added.

That is, as shown in FIGS. 6B and 7, a pair of upper and lower clip members 20 that press the upper and lower joining arms 8 </ b> A and 8 </ b> B from the side are attached to the opening of the hollow portion 13.
Among them, the upper clip member 20 presses the tip side surface of the upper joining arm 8A, and the lower clip member 15 presses the tip side surface of the lower joining arm 8B. As a result, the joining arms 8A and 8B are not laterally displaced in the width direction Z, and are joined on the entire joining surface 12.

[Effect of Fifth Embodiment]
According to the current sensor 1 of the fifth embodiment, the additionally provided clip member 20 functions as a second pressing member that prevents lateral displacement in the width direction Z between the joint arms 8A and 8B. It is possible to prevent the magnetic permeability of the magnetic core 3 from being lowered due to the fact that the bonding surface 12 is not partially bonded due to the lateral shift of Z.

[Other variations]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
For example, in each of the above-described embodiments, a gap formed between the joining arms 8A and 8B and the inner surface of the hollow portion 13 of the bobbin 4 may be filled with resin and hardened.

In this way, the joining arms 8A and 8B and the bobbin 4 can be more securely fixed, and the insulation between the magnetic core 3 and the coil 5 is further improved.
When performing such resin molding, the exposed surfaces of the bobbin 4 and the magnetic core 3 may be entirely molded and coated with resin.

In each of the above-described embodiments, the protruding portion 11 of the second divided core 3B protrudes upward from the base portion of the joining arm 8B to the opposite side to the magnetic sensor 6, and thus is formed on the magnetic core 3. The corners have little influence on the magnetic path.
Therefore, even if there is no protrusion 11, there is almost no influence on the performance of the current sensor 1, and removing this is preferable in terms of contributing to size reduction and weight reduction. Therefore, in each of the above-described embodiments, the second divided core 3B having a shape in which the protruding portion 11 is cut may be employed.

1: Current sensor 2: Gap 3: Magnetic core 3A: First divided core 3B: Second divided core 4: Bobbin 5: Coil 6: Magnetic sensor 8A: Joining arm 8B: Joining arm 11: Protruding portion 12: Joining surface 13: Hollow part 15: Leaf spring member 17: Positioning member 18: Projection part 19: Concave groove part 20: Clip member

Claims (10)

A core split type current sensor in which a magnetic core is divided into a plurality of cores,
A bobbin with a coil wound around its outer peripheral surface;
A plurality of split cores each having a joint arm formed with a joint surface extending in the axial direction of the bobbin, and joining the joint surfaces to each other and superimposing the joint arms. When,
A pressing member that presses the joining surface of one of the joining arms inserted into the bobbin from one opening to the joining surface of the other joining arm inserted into the bobbin from the other opening. A current sensor. The joining surface is composed of a plane whose normal direction is directed to the thickness direction of the joining arm,
The current sensor according to claim 1, wherein each of the divided cores is formed to have the same width dimension in each part including the joining arm.   3. The current sensor according to claim 1, further comprising a positioning member that positions a relative position of the joint arm in the axial direction with respect to the bobbin by uneven engagement between the bobbin and the joint arm.   The current sensor according to claim 1, wherein corner portions that do not affect the magnetic path in the divided core are removed.   The current sensor according to claim 1, wherein the joining arm is housed in the bobbin with a gap with respect to the inner surface of the bobbin.   The current sensor according to claim 1, wherein the pressing member is disposed at a position where the pressing member is in contact with only one of the joining arms to apply a pressing force.   The current sensor according to claim 1, wherein the pressing member is disposed at a position where the pressing member abuts on both the joining arms to apply a pressing force.   The current sensor according to claim 6, further comprising a second pressing member for preventing a lateral shift between the joining arms in the width direction.   The current sensor according to claim 1, wherein the divided core is formed of a magnetic powder molded body.   The current sensor according to claim 1, wherein a gap between the joining arm and the inner surface of the bobbin is hardened with resin.

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